When using the legacy API method, there are three parameters for the Poker_API function:

function Poker_API($url, $params, $assoc)

Set the $assoc parameter to false so that the result is not returned in an associative array. Otherwise, parameters with the same key name will get overwritten. A single tourney results file may contain results from multiple tournaments if they all ran in that day so you will get array elements overwriting elements from other tournaments too. Also, I highly recommend that convert your API calls to the newer JSON method so that the result is returned in a single object. In the case of TournamentsResults, all lines will be returned in a single "Data" array inside that object.